diff --git a/src/metatensor/models/utils/data/readers/structures/__init__.py b/src/metatensor/models/utils/data/readers/structures/__init__.py
index 69e633e73..78457ca29 100644
--- a/src/metatensor/models/utils/data/readers/structures/__init__.py
+++ b/src/metatensor/models/utils/data/readers/structures/__init__.py
@@ -1,4 +1,4 @@
 from .ase import read_structures_ase
 
-STRUCTURE_READERS = {".xyz": read_structures_ase}
+STRUCTURE_READERS = {".extxyz": read_structures_ase, ".xyz": read_structures_ase}
 """:py:class:`dict`: dictionary mapping file suffixes to a structure reader"""
diff --git a/src/metatensor/models/utils/data/readers/targets/__init__.py b/src/metatensor/models/utils/data/readers/targets/__init__.py
index 934d8387a..4536bda04 100644
--- a/src/metatensor/models/utils/data/readers/targets/__init__.py
+++ b/src/metatensor/models/utils/data/readers/targets/__init__.py
@@ -1,13 +1,13 @@
 from .ase import read_energy_ase, read_forces_ase, read_stress_ase, read_virial_ase
 
-ENERGY_READERS = {".xyz": read_energy_ase}
+ENERGY_READERS = {".extxyz": read_energy_ase, ".xyz": read_energy_ase}
 """:py:class:`dict`: dictionary mapping file suffixes to a target energy reader"""
 
-FORCES_READERS = {".xyz": read_forces_ase}
+FORCES_READERS = {".extxyz": read_forces_ase, ".xyz": read_forces_ase}
 """:py:class:`dict`: dictionary mapping file suffixes to a target forces reader"""
 
-STRESS_READERS = {".xyz": read_stress_ase}
+STRESS_READERS = {".extxyz": read_stress_ase, ".xyz": read_stress_ase}
 """:py:class:`dict`: dictionary mapping file suffixes to a target stress reader"""
 
-VIRIAL_READERS = {".xyz": read_virial_ase}
+VIRIAL_READERS = {".extxyz": read_virial_ase, ".xyz": read_virial_ase}
 """:py:class:`dict`: dictionary mapping file suffixes to a target virial reader"""
diff --git a/tests/utils/data/test_readers.py b/tests/utils/data/test_readers.py
index 196eee981..96fdd094f 100644
--- a/tests/utils/data/test_readers.py
+++ b/tests/utils/data/test_readers.py
@@ -21,7 +21,7 @@
 )
 
 
-@pytest.mark.parametrize("fileformat", (None, ".xyz"))
+@pytest.mark.parametrize("fileformat", (None, ".xyz", ".extxyz"))
 def test_read_structures(fileformat, monkeypatch, tmp_path):
     monkeypatch.chdir(tmp_path)
 
@@ -49,7 +49,7 @@ def test_read_structures_unknown_fileformat():
         read_structures("foo.bar")
 
 
-@pytest.mark.parametrize("fileformat", (None, ".xyz"))
+@pytest.mark.parametrize("fileformat", (None, ".xyz", ".extxyz"))
 def test_read_energies(fileformat, monkeypatch, tmp_path):
     monkeypatch.chdir(tmp_path)
 
@@ -70,7 +70,7 @@ def test_read_energies(fileformat, monkeypatch, tmp_path):
         assert result.properties == Labels.single()
 
 
-@pytest.mark.parametrize("fileformat", (None, ".xyz"))
+@pytest.mark.parametrize("fileformat", (None, ".xyz", ".extxyz"))
 def test_read_forces(fileformat, monkeypatch, tmp_path):
     monkeypatch.chdir(tmp_path)
 
@@ -94,7 +94,7 @@ def test_read_forces(fileformat, monkeypatch, tmp_path):
 
 
 @pytest.mark.parametrize("reader", [read_stress, read_virial])
-@pytest.mark.parametrize("fileformat", (None, ".xyz"))
+@pytest.mark.parametrize("fileformat", (None, ".xyz", ".extxyz"))
 def test_read_stress_virial(reader, fileformat, monkeypatch, tmp_path):
     monkeypatch.chdir(tmp_path)